1. Field of the Invention
The present invention relates to high gas barrier packaging films exhibiting good shrinkage and containing an antifog composition for packaging foods and the like. The films are useful for producing modified atmosphere packages that preserve and enhance the shelf life of food and non-food oxygen sensitive items.
2. Description of the Related Art
Containers have long been used to store perishable foods, such as meats, fruits and vegetables, prior to sale in the marketplace to consumers. Maximizing the time in which the food remains preserved in the containers minimizes the amount of spoilage.
The environment around which the food is preserved is an important factor in the preservation process. It is important that the food is maintained at an adequate temperature, while also controlling the molecular and chemical content of the gases surrounding the food. By providing an appropriate gas content to the environment surrounding the food, the food can be better preserved when maintained at the proper temperature or even when it is exposed to variations in temperature. This gives the food producer some assurance that the food will be in an acceptable condition when it reaches the consumer.
Preferred modified atmosphere packaging systems for foods, including raw meats, exposes these foods to extremely low levels of oxygen because it is well known that the freshness of meat can be preserved longer under anaerobic conditions than under aerobic conditions. Maintaining low levels of oxygen minimizes the growth and multiplication of aerobic bacteria.
Many multilayered films for modified atmosphere packaging systems are known. In this regard, U.S. Pat. No. 5,919,547 shows a laminate which delaminates into a substantially gas-impermeable portion and a gas-permeable portion. U.S. Pat. No. 6,060,136 teaches a multilayer film having first and second outer layers and an inner layer. The first and second outer layers comprise a homogeneous ethylene/alpha-olefin copolymer and the inner layer comprises a thermoplastic elastomer. This film is not taught to be heat shrinkable. U.S. Pat. No. 5,766,772 describes multi-layer heat-shrinkable film endowed with anti-fog properties having a different structure from this invention.
It would be advantageous to provide a multilayered packaging film which is heat shrinkable, sealable to a food container and an effective gas barrier. It is also desirable that a film having these properties also have permanent anti-fog properties and are less expensive to manufacture than films of the prior art.
The invention provides a multilayered film which comprises a nylon film attached to a surface of a first polyethylene film via an intermediate adhesive layer, a surface of an ethylene vinyl alcohol film attached to another surface of the first polyethylene film, a surface of a second polyethylene film attached to another surface of the ethylene vinyl alcohol film, and an antifog composition on another surface of the second polyethylene film or incorporated into the second polyethylene film.
The invention also provides a process for producing a multilayered film which comprises coextruding an ethylene vinyl alcohol film to a surface of a first polyethylene film and coextruding a second polyethylene film to another surface of the ethylene vinyl alcohol film; either applying an antifog composition onto another surface of the second polyethylene film or incorporating an antifog composition into the second polyethylene film; and then either coextruding or laminating a nylon film onto another surface of the first polyethylene film via an intermediate adhesive layer.
The invention further provides a food package which comprises a container having an open portion and a multilayered film sealing the open portion; which multilayered film comprises a nylon film attached to a surface of a first polyethylene film via an intermediate adhesive layer, a surface of an ethylene vinyl alcohol film attached to another surface of the first polyethylene film, a surface of a second polyethylene film attached to another surface of the ethylene vinyl alcohol film, and an antifog composition on another surface of the second polyethylene film or incorporated into the second polyethylene film; the multilayered film being positioned such that the antifog composition is on the open portion.
The invention still further provides a multilayered film which comprises a nylon film attached to a surface of an oxygen barrier film, a polyethylene film attached to another surface of the oxygen barrier film via an adhesive layer, and an antifog composition on another surface of the polyethylene film or incorporated into the polyethylene film.
The present invention provides a multilayered packaging film which is heat shrinkable, sealable to a food container and an effective gas barrier. The film of this invention also has permanent anti-fog properties and is less expensive to manufacture than films of the prior art.